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# Asymmetric Encryption Algorithms

## 1. Asymmetric Encryption Algorithms

## 2. Asymmetric Encryption Example

## 3.

.Asymmetric Encryption

Algorithm

DH

Key Length Description

512, 1024, The Diffie-Hellman algorithm is a public key algorithm invented in 1976 by Whitfield Diffie and

Hellman. It allows two parties to agree on a key that they can use to encrypt messages

2048, 3072, Martin

they want to send to each other. The security of this algorithm depends on the assumption that it

4096

is easy to raise a number to a certain power, but difficult to compute which power was used given

Digital Signature Standard 512 - 1024

(DSS) and Digital

Signature Algorithm

(DSA)

RSA encryption

512 to

algorithms

2048

EIGamal

512 - 1024

Elliptical curve

techniques

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the number and the outcome.

DSS was created by NIST and specifies DSA as the algorithm for digital signatures. DSA is a public key

algorithm based on the ElGamal signature scheme. Signature creation speed is similar with RSA, but is 10

to 40 times as slow for verification.

Developed by Ron Rivest, Adi Shamir, and Leonard Adleman at MIT in 1977. It is an algorithm

for public-key cryptography that is based on the current difficulty of factoring very large

numbers. It is the first algorithm known to be suitable for signing as well as encryption, and one

of the first great advances in public key cryptography. Widely used in electronic commerce

protocols, and is believed to be secure given sufficiently long keys and the use of up-to-date

implementations.

An asymmetric key encryption algorithm for public-key cryptography which is based on the DiffieHellman key agreement. Described by Taher ElGamal in 1984 and is used in GNU Privacy Guard

software, PGP, and other cryptosystems. A disadvantage of the ElGamal system is that the encrypted

message becomes very big, about twice the size of the original message and for this reason it is only used

for small messages such as secret keys.

Elliptic curve cryptography was invented by Neil Koblitz and by Victor Miller in the mid 1980s.

Can be used to adapt many cryptographic algorithms, such as Diffie-Hellman or ElGamal. The

main advantage of elliptic curve cryptography is that the keys can be much smaller.

## 4. Diffie-Hellman

## 5. Diffie-Hellman

## 6.

## 7. Secrecy chart

## 8. Homework

• The difference between symmetric and asymmetric encryptionalgorithms: key length, execution speed, using goals and more

• Scorecards of DES, 3DES,AES,SEAL,RC, DSS, DSA, RSA,

ElGamal, DH, Elliptical curve techniques

• Asymmetric Encryption for Confidentiality, Authentication,

Integrity